Measuring device for linear measurements



April 19, 1955 H. GRUBER 2,706,336

MEASURING DEVICE FOR LINEAR MEASUREMENTS Filed Oct. 5, 1951 J/mm'w A4445 M066? U it MEASURING DEVICE FOR LINEAR MEASUREMENTS Application October 5, 1951, Serial No. 249,968

Claims priority, application Germany October 10, 1950 5 Claims. (Cl. '33-69) This invention relates to a portable and handy measuring device for linear measurements, comprising a wire rope Wound on a drum contained in a housing; the unwinding length of said wire rope being pulled out of said housing being indicated by a counter.

Measuring devices for linear measurements comprising a rope drum and a counter measuring the length of the rope having been pulled out are known'as such, but only in a primitive form and with correspondingly inexact measuring results and relatively limited scope of application.

Contrary to this, the measuring device forming the object of the invention is characterised by its exact and faultless functioning and by its versatility of application.

The improvement according to the invention includes roll engaging in the circumferential groove and exerting pressure on the rope guided in said circumferential groove.

Such construction assures a constantly tight and even guiding of the rope as well as an exact transmittal of the extracted length of rope to the counter and thus permits obtaining exact measuring results. According to an especially useful embodiment of the invention a leaf spring acting on the cylinder of the drum, respectively on the rope wound on the drum may be provided in order to obtain a certain pressure against the drum, thereby braking said drum. Such a leaf spring also produces an even winding of the rope, i. e. a winding progressing horizontally over the whole width of the drum, and from one side to the other, without first piling up on one side, then dropping to the other side and piling up there, and

thereby even getting entangled.

According to the invention and in order to further improve the versatility and usefulness of the device a clamping device comprising a set screw and a bore for the passage of the rope is provided between the intermediate pulley and the rope outlet, said clamping device being seated in the housing opposite the rope outlet, and longitudinally sprung in said housing. This permits for instance the use of the device as a plumb, after pulling out the rope and clamping it in the clamping device. Such a clamping device also offers the possibility of unchangeably fixing each measured length, so that the same measurement can be read off and plotted repeatedly, as Well as the possibility of measuring in the dark. The instrument according to the invention also permits measuring forward and backwards and allows the execution of every desired intermediate measurement.

It is also posible to fasten the end of the rope to a point and to measure partial lengths in a continuous manner, clamping the rope after each measurement, readjusting the counter to zero after reading the value obtained and, after loosening the clamping device, to execute the next measurement by further pulling out the rope.

The elastic seating of the clamping device further permits the taking into consideration of the tension exerted on the rope during measuring, as shall be described here after.

In order to increase the instruments scope of application, a graduated circle for reading off angles may be provided on the housing, and the crank arm provided-for {ates Patent the drive of the rope drum may be designed in such a manner, that it can be used for sighting and determining horizontal angles and vertical angles in the manner of a theodolite. In this case the instrument may also be provided with a water level.

Further details and advantages of the invention will be more fully understood from the following description of embodiments according to the accompanying drawing in which:

Fig. l is a view of the measuring device according to the invention taken in the direction of the side of the housing carrying the counter and the rope. drum; Fig. 2 is a view in the same direction, but with the half of the housing (seen in front in Fig- 1) removed, so that the internal parts of the measuring de'viceare to be seen;

Fig. 3 shows an enlarged sectional view of the intermediate pulley and the pressure roll along the line III-III of Fig. 2;

Figs. 4 and 6 are side views ofv the parts of the sight assembly serving as front sight, respectively rear-sight; while Figs. 5 and 7 are the corresponding sectional' views along the line V-V of Fig. 4, respectively along the line VII-VII of Fig. 6. I r I In the figures the numeral 1 designates a housing comprising two parts, the two halves of which are attached to each other by means of screws 1. This housing may be manufactured from light metal or from plastics. The wire rope 2 is wound on the drum 3 carried in the housing, said wire rope leaving the housing through the outlet 5 and carrying on its outer end a, hold ing ring or draw ring 4. When the wire rope 2 is pulled out of the housing on the ring 4 for the purpose of executing a linear measurement, it is being unwound from the rope supply drum 3, thereby passing over the intermediate pulley 6, which possesses a profile comprising a circumferential groove, as shown in Fig. 3.

' Thereby the movement of the intermediate pulleyv 6 is transmitted by means of a worm gear 7 connected with said pulley to the worm 8 driving a counter 9. The ratios are selected in such a manner, that the length of the rope having been pulled out of the, measuring device is bcingindicated by the counter in suitable units of length. The counter can be adjusted to the zero-position in a manner known as such by means of an externally operated re-adjustment knob 10 acting on a bevel gear 11.v

The wire rope 2 guided in the circumferential groove of the intermediate pulley 6 is subjected to pressure exerted by a roll 12 pivotably mounted on the trunnion 13 and being pressed against the wire rope 2 running in the circumferential groove of the intermediate pulley 6 by the effect of a compression spring 14.

The exact diameter of the circumferential groove of the intermediate pulley 6 being of substantial importance for the exactness of measurement, said intermediate pulley is provided with a special outer rim 6, which is radially slotted at a point designated by S in Fig. 2. Two small columns 15 and 15 are mounted on the outer rim on both sides of the slot, said columns possessing bores perpendicular to the direction of said slot with an adjusting screw 16 engaging through these bores. By turning this adjusting screw 16 the width of slot S and consequently the outer diameter of the rim 6' can be changed within narrow limits, in order to adjust the measuring device.

Between the intermediate pulley 6 and the rope outlet 5 the wire rope 2 is led through a resiliently seated clamping device 17 comprising a bore in the direction of the rope in which said rope can be clamped by means of the set screw 18. The clamping device 17 is subjected to the pressure of a spring 19 which normally presses it against an abutment. By means of this clamping device the rope having been pulled out can be clamped at different lengths, for instance when it is desired to measure several partial lengths issuing from one point, whereby after each measuring of a partial length the rope is clamped in the clamping device and the counting device is re-adjusted to the zero-position after reading off the result. In addition to this, the clamping device 17 co-operates with a notch or mark 20 provided on the housing in such a manner, that for the execution Patented Apr. 19, 1955 l of very exact measurements the tension exerted on the rope can be taken into consideration. For this purpose the tension exerted on the rope must be such, that a mark provided on the clamping device 17 coincides with the mark 20 providedon the housing. This assures that the measurement has been executed with the tension upon which the calibration of the device was based.

The rope outlet 5 comprises a narrow bore which is exactly adapted to the rope diameter, so that any dirt which might adhere to the rope having been pulled out is automatically wiped off when re-winding said rope.

For re-winding the rope after it has been pulled out, the crank 22 mounted on the crank arm 21 is operated, said crank driving the rope drum 3. The numeral 23 designates 'a' leaf spring, which presses against the cylinder of the rope drum 3, respectively on the layer of rope wound on the drum. This results in aslight braking of the rope drum 3 as well as in the ropes being wound and unwound in even layers.

In order to permit the use of the measuring device also for measuring angles and heights, it is provided with a graduated circle 24 for reading off angles cooperating with the crank 22. The crank arm 21 is equipped with the mirror 25 and besides that is designed in the manner illustrated for sighting and determining horizontal and vertical angles. For this purpose a water level 26 for finding the horizontal plane in determining of angles is mounted on the crank arm 21. Two additional water levels 27 and 28 for determining the horizontal and vertical plane are provided on the housing 1, and which are used by placing the measuring device with the plane of contact points A and B against the horizontal or vertical surface to be checked.

Instead of the separate water levels 27 and 28 the water levels 29, 30 which are designed as a single unit and indic'ated'in the drawing by broken lines-may be mounted on the housing.

" A threaded bush 31 is provided, by means of which the measuring device may be screwed onto a tripod if desired.

Two sight parts 32 and 33 are provided on the crank arm 21, through which (for example in the case of height measurement) the object to be measured can be sighted at.

The design of the sight parts 32 and 33 is illustrated in Fig. 4 respectively in Fig. 6 in conjunction with the corresponding Figures 5 and 7. The sight part 32 serves as front sight, the sight part 33 as rear sight. In case of horizontal sighting the two edges 34 and 35 must coincide, while in case of vertical sighting the edges 36 and 37 must be in alignment. Thereby the two points converge in a sharp angle which prevents blinding by sun glare. The exactness obtainable with such a construction is of special importance in view of the short distance between front sight and rear sight, relative to the length of the line of sight.

I claim: 1. A measuring device for linear measuring comprising a housing, a rope drum rotatably mounted in said housing, a crank arm externally of said housing and con nected to said drum for imparting rotational movement to said drum, a wire rope wound on and adapted to be wound on and off said drum, a rope outlet in said housing adjacent one side of said drum, an intermediate pulley located on an opposite side of said rope drum with respect to said outlet and having a. circumferential groove, said rope extending from said drum around at least half the circumference of said pulley in frictional driving engagement therewith and then through said outlet, means outside of said outlet for pulling said rope out of said housing, mechanical counting means coupled to said intermediate pulley for indicating the length of the Wire rope pulled out, said rope having driving engagement with said intermediate pulley in the circumferential groove thereof and being guided in said rope outlet, spring pressed roll means engaging said rope running in said groove, a clamping device having a bore therein for the passage of said wire and longitudinally displaceable in said housing, second spring means for opposing the longitudinal movement of said device, and a set screw for clamping said wire rope in said bore, said clamping device being mounted in said housing between said intermedate pulley and said rope outlet.

2. A measuring device as in claim 1 further comprising a graduated circular sector delineated on said housing concentric with the axis of said crank arm, and sighting means on 'said crank arm whereby vertical and horizontal angles can be measured.

3. A measuring device as in claim 2 further comprising a water level mounted on said crank arm for determining a horizontal plane.

4. .A measuring device as in claim 3, further comprising a second water level on said housing for determining a horizontal plane-and a third water level on said housing for determining a vertical plane. 5. A measuring device as in claim 4, further comprismg two contact points on said housing lying in a plane and adapted to be placed against a surface to determine the vertical or horizontal plane.

References Cited in the file of this patent UNiTED STATES PATENTS ll4,ll4 Dimock Apr. 25, 1871 l56,586 vMcNeill Nov. 3, 1874 2,271,742 McCullough Feb. 3, 1942 2,553,613 True May 22, 1951 Y Y FOREIGN PATENTS 15,101 Great Britain June 28, 1911 203,958 Great Britain Sept. 20, 1923 399,567 Great Britain Oct. 12, 1933 

